Typically, a mobile terminal is designed to operate in one of the normal and speakerphone modes for voice communication. Here, the normal mode is the operation mode in which the user communicates by placing the mobile terminal near his/her ear, and the speakerphone mode is the operation mode in which the user communicates using the speakerphone while maintaining a distance from the mobile terminal. Recently, it is a trend that the mobile users tend to use smartphone which is provided with a relatively large display and a loudspeaker appropriate for supporting various multimedia functions. With the advance of communication and data processing technologies, the smartphone is evolving to communicate and process the high quality multimedia data such as high resolution video and audio data and, as the consequence, it is leading the improvement of the display and speakerphone performance so as to provide the user with crystal clear audio and video.
FIG. 1 illustrates a rear perspective view and a front view of a conventional mobile terminal.
As shown in FIG. 1, the conventional mobile terminal is provided with a pair of microphone MC1 and speaker SP1 at the bottom of the body and another pair of microphone MC2 and receiver SP2 at the top of the body. Here, the speaker SP1 is the main speaker to output audio at high quality level in multimedia playback. In the above-structured mobile terminal, the voice communication can be progressed in one of the speakerphone mode and normal mode by switching between the auxiliary microphone MC2 and the main microphone MC1 using a switch in the codec. In this example, the normal mode is turned on with the activation of the receiver SP2 at the top and the main microphone MC1 at the bottom, and the speakerphone mode is turned on with the activation of the speaker SP1 and the auxiliary microphone MC2. The reason why the conventional mobile terminal is equipped with two microphones and two speakers is that the closely arranged speaker and microphone cause echo. In order to avoid the echo caused by activating the speaker SP1 and the main microphone MC1 simultaneously, the auxiliary microphone MC2 is enabled in pair with the speaker SP1.
For this reason, the conventional mobile terminal has been designed to have two microphones MC1 and MC2 and two speakers SP1 and SP2. In case the mobile terminal uses the speaker SP1 independently, it is necessary to have two microphones, one receiver speaker, and an independent speaker, resulting in requirement of additional parts such as microphone MC2 and a Low Dropout (LDO) for supplying power to the microphone MC2.